Such a nut is known by e.g. GB Pat. No. 22514/1899. The nut can be easily and effectively locked in any desired position on a threaded member without the position of the nut being influenced by the clamping force necessary to achieve the locking action.
One disadvantage of the known nut is that the element which is displaceable radially in the nut and is pressed against the thread co-operating with the nut during the locking action has a tendency to obstruct the turning of the nut even when the means used to press the element against the thread has ceased to act on the element, since no positive returning force affects the element, which therefore because of friction and possibly other mechanical or chemical influence, e.g. after a prolonged period of staying tightened, runs the risk of remaining in operative position against the thread, thereby breaking the turning of the nut when the nut is unscrewed. Handling of the nut is also complicated because the parts of the nut are not self-contained before the nut is mounted on e.g. a screw or a threaded journal, and the locking element can then easily fall off the radially inwardly open recess in which it is intended to be positioned.